Superoxide, or univalently reduced oxygen, is a reactive free radical which is produced by many enzymatic and non-enzymatic reactions in biological systems. We have established that superoxide dismutase, an enzyme which efficiently scavenges the radical, is ubiquitously distributed throughout aerobic organisms. It has been shown that mutant E. coli, deficient in the enzyme, cannot survive in an aerobic environment. There is a great deal of evidence which suggests that O minus 2 is abundantly produced in vivo and is capable of inflicting serious damage to cell components. One purpose of this research project is to investigate the roles of O minus 2 and superoxide dismutase in human genetic diseases such as heriditary spherocytosis and other hemolytic anemias. It also seems appropriate to examine the reactions of O minus 2 with specific biological molecules, particularly those found extracellularly (e.g. transferrin, hyaluronic acid) where no superoxide dismutase is present to offer protection. We have recently observed that O minus 2 causes depolymerization of hyaluronic acid in vitro. This suggests a possible role in arthritic diseases which are characterized by decreased viscosity of synovial fluid or impaired mucin clot formation. Specific objectives and methods include a survey of superoxide dismutase activity in erythrocytes of patients observed by the Department of Hematology as having hemolytic anemias. Much in vitro experimentation is planned to observe the effects of exposure of red cells to the radical, as well as the chemical and physical effects of the radical on isolated components, such as peroxidation of unsaturated lipids, reduction of iron-transferrin, or depolymerization of polysaccharides.